JPS5899017A - Manufacture for piezo-resonator component - Google Patents

Abstract

PURPOSE:To obtain inexpensive piezo-resonator componets, by obtaining the piezo-resonator a prescribed size from a mother piezo-electric plate having electrodes by means fo a dicing saw and manufacturing the electrodes on one surface split into two. CONSTITUTION:A groove 3 is provided on one major surface of a ceramic base 2 toward lengthwise direction l to divide the surface into two equally. Grooves 4, 5 are provided at 1/3l from the lengthwise center respectively in orthogonal to the lengthwise direction. An input electrode 6, an output electrode 7, independent electrodes 8-11 are provided on one major surface of the base 2 by being sectioned with the grooves 3-5. A full surface electrode 12 is provided on the other major surface to obtain a resonator of the length oscillation mode expanded and contracted toward the direction l. Piezo-resonators 1 of a prescribed size are cut out by using a dicing saw 13 and the grooves 3-5 are formed. Through the manufacture like this, since the resonators with little dispersion in characteristics can be manufactured with high manufacture efficiency, they can be produced inexpensively.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a piezoelectric resonant component such as a piezoelectric filter.

For example, the center frequency of a piezoelectric filter for an AM receiver is several 100 kHz, for example 450 kHz,
From various viewpoints such as mass productivity, there are the following three types of filter structures. The first is a Yurmann-shaped filter. This filter requires an IFT, and has the following disadvantages: 1) It is difficult to match the EFT and the piezoelectric resonator, 2) The reliability of the coil is low, 2) It is large, and 2) It is expensive.

The second type is a three-terminal filter that uses the spreading vibration mode of a square plate and the radial vibration mode of a disc. This filter is: - Relatively large. Especially when using the third harmonic of a disc, the size becomes a problem. - In the case of a square plate, spurious vibrations due to the circular vibration mode are strongly excited. ,
There are drawbacks such as. The third is a filter that utilizes the knee heavy mode of longitudinal vibration of a rectangular plate. This filter has two problems: ■It is difficult to adjust the two resonators, ■It has a complicated structure,
■It has drawbacks such as being expensive.

The present invention has various features and is a piezoelectric resonant component having a structure completely different from that described above.
ii This is related to the manufacturing method and has the following objectives.

The purpose of this invention is to provide an inexpensive piezoelectric resonant component.

Another object of the present invention is to provide a piezoelectric resonant component with small variations in characteristics from product to product.

Another object of the present invention is to provide a piezoelectric resonant component with excellent manufacturing efficiency.

That is, the gist of the present invention is to obtain a piezoelectric resonant element of a predetermined size from a base piezoelectric plate having electrodes using a dicing saw, and to separate the electrodes on at least one surface side into two parts. This is a method of manufacturing a piezoelectric resonant component.

Embodiments of the invention will be described below with reference to the drawings.

Figure 1 shows a piezoelectric resonant element 1, which is a component of a piezoelectric resonant component.
shows. In the figure, reference numeral 2 denotes a piezoelectric ceramic substrate, and one main surface thereof is provided with a groove 3 extending along the length p direction. Divided into thirds in the direction. Also, the length! 4.5 in the direction intersecting the direction, respectively, are provided at positions 1/3Q from the center in the length direction. Therefore, on one main surface of the substrate 2, an input electrode 6,
An output electrode 7 and independent electrodes 8 to 11 are provided separated by grooves 3 to 5. Furthermore, a full-surface electrode 12 is provided on the other main surface of the substrate 2 . Then, a length vibration mode that expands and contracts in the length ρ direction is used, and the dimensions of each part of the male plate 2 are, for example, when the center frequency is 450 kHz, the length ρ is about 4.05111, the width is 0.6 cm, Thickness is 0.3w++, depth of groove 3 is 0.15Ill steel, groove 3
The width of is 0.15g+s, the depth and width of $4.5 are:
Any suitable method may be used since the electrode 6.7 is simply electrically isolated from the electrode 8 or 9.10 or 11.

FIG. 2 shows the voltage of the piezoelectric resonant element 1 shown in FIG.

Shows an emotional symbol. In this way, the piezoelectric resonant element 1 shown in FIG. 1 can be used as a filter element using single mode vibration in the longitudinal direction.

A method of manufacturing this piezoelectric resonant element 1 will be explained below. - Rectangular plate-shaped ceramic sintered body 101 with sides on the order of several cm
Prepare the surface by wrapping. Electrodes are provided on the opposing main surfaces. This electrode is an electrode for polarization processing, and also serves as electrodes 6 to 12. As shown in FIG. 3, the ceramic sintered body 101 imparted with piezoelectricity by polarization treatment is assembled in large numbers in order to increase manufacturing efficiency, and is used to generate piezoelectric resonance of a predetermined size using a dicing saw 13. At the same time as cutting out the element 1, grooves 3 to 5 are formed. That is, according to the dicing saw 13, the cutting accuracy is as high as ±2μ, so it is possible to cut out the piezoelectric resonant element 1 having an accurate length β, and compared to the conventional manufacturing method, frequency selection,
Processes such as frequency adjustment can be omitted. For example, when it was desired to obtain one with a center frequency of 455 kl-1z, the variation in the center frequency was kept within a maximum of 1.2 kHz. In addition, by forming 3 to 5 electrodes, the input electrode 6 and output electrode 7 having the necessary external dimensions can be obtained by reusing the polarized electrodes. In this respect, the conventional manufacturing method involves printing the pattern of the vibrating electrode on the polarized bond and the polarized electrode with resist ink, and etching it, so it can be said that the present invention is clearly simpler. The groove 4.5 has the length P of the input electrode 6 and the output electrode 7 equal to 2/3·ρ, and has the effect of suppressing the third harmonic. Therefore, electrodes 8 to 11 are idle. The dicing saw 13 has a blade that rotates at high speed and moves in the direction of the arrow in FIG. 4, and although it cannot cut deeply, it is useful for cutting piezoelectric plates as thick as the object of the present invention.

Further, by moving the dicing saw 13 in the eight directions indicated by the arrows in FIG. 4 and setting appropriate values, it is possible to perform cutting and to form grooves of arbitrary depth. Therefore, one method for cutting or forming grooves is to temporarily fix a plurality of piezoelectric elements 1 together and form grooves in the horizontal direction in the figure, as shown in FIG. After cutting, it is efficient to form grooves and cut in the vertical direction in the figure.

5 to 7 show the base 14, and the base 14 includes an input/output terminal plate 15, a conductive rubber sheet 16, which will be described later.
The positional relationship of the phase n between the piezoelectric resonant element 1 and the ground terminal plate 17 is regulated to be 'aAII'. As will be described later, when these internal elements are inserted into the case 1B, the shape and dimensions of the ground terminal plate 17 relative to the inner wall surface of the case 18 are designed so that an appropriate contact pressure is maintained between the ground terminal plate 17 and the piezoelectric resonant element 1. I'm trying to get it. The base 14 has the following structure. Walls 20.
20 is provided integrally with part 19, and low 1
21.21 is provided integrally. In addition, these walls 20,
20, 21. Inside surrounded by 21, there is a pair of columnar bodies 2.
2, 22, and a set of four columnar bodies 23, 23.2323 are provided integrally with the portion 19, respectively. Then, the input/output terminal board 15 is attached as symbolically shown by the dashed line in the figure.

As shown more clearly in FIG. 8, the input/output terminal board 15 is
It has an input terminal portion 24 and an output terminal portion 25. The input terminal portion 24 is located between the right end of the lower wall 20 and the lower end of the right low wall 21, between the right columnar body 22 and the right low wall 21, and between the upper 120 and the upper right corner in the 50th section. It is fitted into each gap between the columnar body 23 and between the upper left columnar body 23 and the upper right columnar body 23.

The output terminal portion 25 is located on the left side of the low wall 21 in FIG.
Between the lower end of and the left end of the lower 120, the lower left columnar body 23
and the lower wall 20, and between the columnar body 23 on the lower left and the columnar body 23 on the lower right. As is clear from the figure, a taber is provided at the bottom to facilitate fitting.

Next, in FIG. 5, a conductive rubber sheet 1G as shown in FIG. 9 is placed in the area surrounded by the four columnar bodies 23, 23, 23, and 23. Furthermore, the piezoelectric resonant element 1 is placed on the rubber sheet 16 with the grooves 3 to 5 facing down. The piezoelectric resonant element 1 is regulated in position by a pair of columnar bodies 22 and four columnar bodies 23 of the base 14. Then, the input terminal portion 24 and the output terminal portion 2 of the input/output terminal board 15
Each tip 26.27 of 5 is an input electrode 6 of the piezoelectric resonant element 1.
, comes into contact with the output electrode 7 via the conductive rubber sheet 16. The rubber sheet 16 of 9 is called an anisotropically conductive rubber sheet, and is composed of, for example, graphite fibers or thin metal wires embedded in the thickness direction of a silicone rubber sheet. It exhibits insulation properties in the lateral direction. Therefore, the input electrode 6 and the output electrode 7 of the piezoelectric resonant element 1 are connected to the input terminal portion 2 through the anisotropic conductive rubber sheet 1G without mutual short circuit.
4 and the tip 27 of the output terminal portion 25.

The ground terminal plate 17 is shown more clearly in FIGS. 10-12. The ground terminal plate 11 has a lead portion 28 integrally formed with a substantially H-shaped tip 29, and a contact protrusion 2 at the center.
It has 91. As shown in FIGS. 10 and 12, the distal end portion 29 has an arcuate shape and is provided with necessary elastic force. Further, a portion of the lead portion 28 accommodated in the case 18 has a portion 30 bent into a substantially crank shape.

Depending on the degree of bending, the tip portion 29 and the lead portion 28
are not parallel, but so that their extension lines intersect (
- For example, set the intersection angle to 0-10°).

The shape of the case 18 is shown more clearly in FIGS. 13 to 15. As shown in the figure, Taber 3 is used to provide directionality.
1, an opening 3 is formed on the bottom surface of the approximately box-shaped molded body having
It has 2. The inner space 33 has a convex cross-section expanding toward the back so as to resemble the outer shape of the base 14.

The edge of opening 32 has a taper 34 to facilitate insertion of internal components.

FIG. 16 shows the base 1 in relation to this invention.
4, the input/output terminal board 15, the rubber sheet 16, and the piezoelectric resonant element 1 are stacked, and the lead frame of the ground terminal board 17 is stacked on the lead frame connection part of the input/output terminal board 15, and the ground terminal board 17 is stacked. This figure shows a state before the piezoelectric resonator 1 is inserted into the case 18, with the contact protrusion 291 pressed into contact with the center position of the entire surface electrode 12 of the piezoelectric resonator 1. As is clear from the figure, when looking at the assembled internal elements to be inserted into the case 18 from the side, the ground terminal plate 1
The molded shape of 7 makes it look like a wedge. When the internal element of the case 1 is inserted in this state, the end portion 29 and the bent portion 3o of the ground terminal plate 17 are pressed against the inner wall surface of the case 18, and due to the reaction force, the ground terminal plate 11 is Appropriate pressure is applied to the piezoelectric resonant element 1, the conductive rubber sheet 1G, and the input/output terminal board 15 located between the base 14, and after the insertion is completed, the ground terminal board 17 is shaped like an arch as described above. The contact pressure necessary to hold the piezoelectric resonant element 1 can be obtained by the elastic force caused by this and the elastic force of the rubber sheet 16.
Each component is housed in the case 18 without any misalignment.

Note that FIGS. 17 to 19 show the state of the finished product. The lead portion 28 of the ground terminal plate 17 is inserted into the recess 2 located in the center of the lower wall 2o of the base 14 in FIG.
I'm hooked on 01.

The open part 32 of the case 18 is made of a general sealing resin 3.
It is sealed by 5. At this time, since the lower wall 20 of the base 14 in FIG. 5 closes most of the opening 32, sealing is ensured and excess resin does not go around inside. Generally speaking, it goes without saying that the smaller the size of the opening, the more securely the opening can be sealed. However, the smaller the opening, the more difficult it becomes to insert internal components through the opening of the case.

As described above, in the present invention, the entire internal parts are assembled into a wedge shape before being inserted, so even if the opening is small, insertion becomes easy, and assembly by machine is possible. Therefore, automatic assembly is possible. This has the synergistic effect of not only being possible but also ensuring sealing.

FIG. 20 shows a selection characteristic curve of a filter using one piezoelectric resonant element according to the present invention. FIG. 21 shows the selection characteristic curve of a device in which one IFT is further connected in cascade.

FIG. 22 shows a selection characteristic curve for a piezoelectric connection according to the invention. FIG. 23 shows the selection characteristic curve of a device in which one rFT is further connected in cascade. FIG. 24 shows spurious characteristics of a filter in which two piezoelectric resonant elements and an IFT-type piezoelectric resonant element according to the present invention are connected in cascade.

As is clear from the above description, the present invention uses a dicing saw to obtain a piezoelectric resonant element of a predetermined size from a soup stock plate having electrodes, and also to separate the electrode on at least one surface side into at least two parts. This method of manufacturing a piezoelectric resonant component is characterized by the following effects.

According to this invention, a step of printing a vibrating electrode pattern of a multi-element valve on a base piezoelectric substrate with resist ink, a step of removing unnecessary electrode portions by etching, a step of cutting out elements with predetermined dimensions from the base piezoelectric substrate, a polishing step, The process of classifying products by center frequency and the process of adjusting the center frequency to a predetermined value can be reduced to one process of electrode processing using a dicing saw and cutting out elements.

According to this invention, the stray capacitance between the input and output is small, so compared to the conventional three-terminal filter that uses the spreading vibration mode of a square plate, the selection characteristic curves on the high-frequency side and the low-frequency side with the center frequency as a boundary. has good symmetry.

It goes without saying that the shape of the piezoelectric resonant element, the vibration mode used, the shape of the electrodes, etc. to which the present invention can be applied are not limited to the above-described embodiments.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a piezoelectric resonant element, Fig. 2 is an electrical symbol diagram of the one shown in Fig. 1, Fig. 3 is a front view of a plurality of ceramic sintered bodies, and Fig. 4 explains the present invention. Figure 5 is a front view of the base, Figure 6 is a cutaway view of the base, Figure 7 is a cutaway view of the base, and Figure 8 is a cutaway view of the base. A stop view of the terminal board, FIG. 9 is a front view of the rubber sheet, and FIG. 10 is a top view of the ground terminal board.
Fig. 11 is a front view of the case, Fig. 12 is a side view of the case, Fig. 13 is a side view of the case, and Fig. 14 is a front view of the case.
FIG. 15 is a bottom view of the same, FIG. 16 is an exploded sectional view of the piezoelectric resonant component according to the present invention, and FIG. 17 is a front view of the same.
Fig. 18 is a sectional view of the same, Fig. 19 is a broken view seen from the bottom, Figs. 20 to 23 are selection characteristic curve diagrams, and Fig. 24
The figure is a spurious characteristic curve diagram. 1...Piezoelectric resonant element, 2...Piezoelectric ceramic substrate, 3-5...Groove, 6...Input electrode, 7... Output electrode, 8 to 11...
・Independent electrode, 12...Full surface electrode, 13...
・・Dancing Saw, 14・・・・Base, 15・
...Input/output terminal board, 16...Conductive rubber sheet, 17...Earth terminal board, 18...
...Case, 19...Rectangular plate-shaped part, 20
...Wall, 21...Low wall, 22...
... Column, 23... Column, 24...
・Input terminal part, 25... Output terminal part, 26
...Tip, 27...Tip, 28...
...Lead part, 29...Tip part, 30...
...Bending part, 31...Taper, 32
...Opening, 33...Inner space, 34.
...Taber, 35...Sealing resin, 1
01... Ceramic sintered body, 291...
・Contact protrusion. Patent application Murata Manufacturing Co., Ltd. Figure 3 / Figure 4 m / θl Figure 3 Chrysanthemum Figure 9 Figure 1.3 Figure 1 Cocoon! Figure 4 Octopus Figure 15 Blade

Claims (1)

[Claims] From a mother piezoelectric plate with electrodes, using a dicing saw,
1. A method of manufacturing a piezoelectric resonant component, characterized in that a piezoelectric resonant element of predetermined dimensions is obtained, and an electrode on at least one surface side is separated into at least two.